Eight millions years ago [8 mya] our ancestors were normal animals. They were apes. Our ‘nephews’, the chimpanzees and the bonobos, still are apes and normal animals. Apes live in rainforests. When the place where our earliest ancestors lived had not been changed, we would still be apes and normal animals.

However, from 10 mya the climate was becoming cooler and dryer. Rainforest needs heat and wetness; so the rainforest belt, in early Miocene reaching over southern France and Italy, shrank and 8 mya our ancestral jungle turned slowly into open savannah. It is here where our story begins.

Frans de Waal (Bonobo 1997) says that, when we want an image of our earliest ancestors, we can look at the bonobos. They are the only kind of chimpanzee whose environment never changed. A species only changes when its environment changes. The environment of our earliest ancestors changed totally, so our earliest ancestors changed totally. The environment of the ancestors of the chimpanzees changed much later and somewhat, so the chimpanzees changed somewhat.

Here, we will name our earliest ancestors ‘our ANBOS’ (ancestor-bonobos).

It took tens of hundred thousands of years for their jungle to turn into a savannah. The ANBOS never had any idea of this change; for them the world was in every phase like it always was. So the adaptations to the new conditions passed unnoticed. But for our story these adaptations are crucial.

The savannah is a diversified environment consisting of open woodlands mixed with impenetrable shrubs and grasslands accommodating herds of many kinds of grass eaters.

Our ANBOS lived in the woodlands, where they spent the nights in nests high in the trees. But these woodlands along the shores of rivers and lakes didn’t contain the fruit trees their ancestors used for sustenance. For their food, our ANBOS had to roam the open grasslands which was very dangerous because of the big cats that preyed on the grass eaters. Big lions, sabre toothed tigers and similar species were formidable predators. The sabre toothed tigers were specialists in preying on pachyderms: rhinoceroses, hippopotamuses and (ancestors of the) elephants. In a short sprint the sabre tooth ran under them and ripped open their bellies with their sabre teeth. The mighty colossus was felled and after his downfall the ‘tiger’ fed on the entrails only. The sabre teeth were too frail for the rest of the cadaver. The rest of the carrion was left to the giant hyenas. Nature is cruel and doesn’t know empathy.

What I emphasize: the Miocene (22 – 5 mya) savannah was characterised by megafauna and was much more dangerous than the current Serengeti. Though the little ANBOS were much stronger than we are now, they needed special armament to roam the grasslands safely. As normal apes, they protected themselves by throwing anything they could grasp at their predators.

Jane Goodall tells the story of Mister Worzle. The bananas she put down for the chimpanzees in order to keep them in her neighborhood for studying their behaviour, also allured baboons (a large and brave monkey) who frightened some female chimpanzees. But Mister Worzle did not give a centimeter of ground and threw anything he could grasp: grass, branches, one time a bunch of bananas (the baboons were happy!). But soon he discovered that stones worked and soon found out that bigger stones worked even better.